docs: def __find_args_separator(self, decl_string, start_pos):
          """implementation details"""
          bracket_depth = 0
          for index, ch in enumerate(decl_string[start_pos:]):
              if ch not in (self.__begin, self.__end, self.__separator):
                  continue  # I am interested only in < and >
              elif self.__separator == ch:
                  if not bracket_depth:
                      return index + start_pos
              elif self.__begin == ch:
                  bracket_depth += 1
              elif not bracket_depth:
                  return index + start_pos
              else:
                  bracket_depth -= 1
          return -1